ben-nanonote: import ben-nanonote machine support

Import Ben Nanonote machine support files from "oe-classic".
This is intended to be used by the JLime distribution.

The following changes were done to comply with oe-core rules:
- use DEFAULTTUNE from conf/machine/include/tune-mips32.inc in oe-core
  repository instead of setting TARGET_ARCH,
- remove IMAGE_FSTYPES setting, this is done in distro configuration.

Signed-off-by: Apelete Seketeli <apelete@seketeli.net>